. | . |
SwRI scientists identify a possible source for Charon's red cap by Staff Writers San Antonio TX (SPX) Jun 22, 2022
Southwest Research Institute scientists combined data from NASA's New Horizons mission with novel laboratory experiments and exospheric modeling to reveal the likely composition of the red cap on Pluto's moon Charon and how it may have formed. This first-ever description of Charon's dynamic methane atmosphere using new experimental data provides a fascinating glimpse into the origins of this moon's red spot as described in two recent papers. "Prior to New Horizons, the best Hubble images of Pluto revealed only a fuzzy blob of reflected light," said SwRI's Randy Gladstone, a member of the New Horizons science team. "In addition to all the fascinating features discovered on Pluto's surface, the flyby revealed an unusual feature on Charon, a surprising red cap centered on its north pole." Soon after the 2015 encounter, New Horizons scientists proposed that a reddish "tholin-like" material at Charon's pole could be synthesized by ultraviolet light breaking down methane molecules. These are captured after escaping from Pluto and then frozen onto the moon's polar regions during their long winter nights. Tholins are sticky organic residues formed by chemical reactions powered by light, in this case the Lyman-alpha ultraviolet glow scattered by interplanetary hydrogen atoms. "Our findings indicate that drastic seasonal surges in Charon's thin atmosphere as well as light breaking down the condensing methane frost are key to understanding the origins of Charon's red polar zone," said SwRI's Dr. Ujjwal Raut, lead author of a paper titled "Charon's Refractory Factory" in the journal Science Advances. "This is one of the most illustrative and stark examples of surface-atmospheric interactions so far observed at a planetary body." The team realistically replicated Charon surface conditions at SwRI's new Center for Laboratory Astrophysics and Space Science Experiments (CLASSE) to measure the composition and color of hydrocarbons produced on Charon's winter hemisphere as methane freezes beneath the Lyman-alpha glow. The team fed the measurements into a new atmospheric model of Charon to show methane breaking down into residue on Charon's north polar spot. "Our team's novel 'dynamic photolysis' experiments provided new limits on the contribution of interplanetary Lyman-alpha to the synthesis of Charon's red material," Raut said. "Our experiment condensed methane in an ultra-high vacuum chamber under exposure to Lyman-alpha photons to replicate with high fidelity the conditions at Charon's poles." SwRI scientists also developed a new computer simulation to model Charon's thin methane atmosphere. "The model points to 'explosive' seasonal pulsations in Charon's atmosphere due to extreme shifts in conditions over Pluto's long journey around the Sun," said Dr. Ben Teolis, lead author of a related paper titled "Extreme Exospheric Dynamics at Charon: Implications for the Red Spot" in Geophysical Research Letters. The team input the results from SwRI's ultra-realistic experiments into the atmospheric model to estimate the distribution of complex hydrocarbons emerging from methane decomposition under the influence of ultraviolet light. The model has polar zones primarily generating ethane, a colorless material that does not contribute to a reddish color. "We think ionizing radiation from the solar wind decomposes the Lyman-alpha-cooked polar frost to synthesize increasingly complex, redder materials responsible for the unique albedo on this enigmatic moon," Raut said. "Ethane is less volatile than methane and stays frozen to Charon's surface long after spring sunrise. Exposure to the solar wind may convert ethane into persistent reddish surface deposits contributing to Charon's red cap." "The team is set to investigate the role of solar wind in the formation of the red pole," said SwRI's Dr. Josh Kammer, who secured continued support from NASA's New Frontier Data Analysis Program.
Research Report:"Extreme Exospheric Dynamics at Charon: Implications for the Red Spot"
Gemini North Telescope Helps Explain Why Uranus and Neptune Are Different Colors Washington DC (SPX) Jun 01, 2022 Astronomers may now understand why the similar planets Uranus and Neptune are different colors. Using observations from the Gemini North telescope, the NASA Infrared Telescope Facility, and the Hubble Space Telescope, researchers have developed a single atmospheric model that matches observations of both planets. The model reveals that excess haze on Uranus builds up in the planet's stagnant, sluggish atmosphere and makes it appear a lighter tone than Neptune. Neptune and Uranus have much in commo ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |